This invention relates to surgery, and more particularly to hands-free surgical retractors of the kind in which one or more tissue-engaging elements are mounted on a frame which is supported on the patient""s body.
The principal retractors of the type to which this invention relates include rib spreaders and sternal spreaders. Most of these spreading retractors have a three-sided, rectangular frame comprising a pair of arms, a first one of which is fixed in perpendicular relation to a rack, and the other of which is movable along the rack in parallel relation to the first arm by a crank-operated pinion. Other retractors to which the invention is applicable include retractors having closed frames of various shapes such as circular, oval or rectangular. Retractors in accordance with the invention are primarily used as rib or sternum retractors. However the invention has utility in various hands-free thoracic and abdominal retractors.
A typical three-sided, hands-free, rib spreading or sternum spreading retractor has one or more blades on each of its two parallel arms for engaging the chest wall. The blades adequately grasp the opposed parts of the chest wall in most patients. However, in the case of an obese patient, the layer of fat overlying the chest wall, may hold the parallel arms of the retractor at a height so far above the chest wall that the blades cannot extend to a depth sufficient to grip the chest wall adequately. For this reason it is generally necessary to utilize a specially designed retractor with an obese patient. Alternatively, in the case of a retractor having removable blade assemblies, such as that described in U.S. Pat. No. 4,852,552, granted Aug. 1, 1989, it is possible to substitute special, extra long, blades for the standard blades.
In various kinds of surgery it is desirable to mount various auxiliary devices on the arms of a spreading retractor. In heart valve surgery, for example, it is common for a surgeon to support one or more heart valve retractors on vertical posts or T-shaped supports removably connected to a spreader arm. Similarly, in xe2x80x9cbeating heartxe2x80x9d bypass surgery, a heart stabilizer may be secured to the spreader for the purpose of immobilizing, or at least limiting the motion of, the portion of the heart wall on which a bypass graft is to be carried out.
It is desirable to be able to position these auxiliary devices at any desired location on an arm of a spreading retractor, and to be able to move the auxiliary device easily from one location to another on the spreader arm. However, in conventional spreader retractors, the blades, or elements which connect the blades to the spreader arms, interfere with the movement of the auxiliary devices along the arms, and require the auxiliary devices to be removed and reattached to the arms if they need to be repositioned. Moreover, the blades and their connecting elements limit the positions at which auxiliary devices can be attached to the spreader arms.
The principal object of this invention is to provide an improved hands-free retractor which can be used with obese as well as with average patients. Another object of the invention is to provide a hands-free retractor on which auxiliary instrument supports can be readily mounted at any desired location and moved easily from one location to another. It is also an object of the invention to provide a hands-free retractor which combines the above advantages; i.e., one that has the ability to be used satisfactorily with an obese patient, the ability to accommodate an auxiliary instrument support at any desired position on its arms and the ability to allow sliding movement of an instrument support along the length of each arm.
A preferred surgical retractor in accordance with the invention comprises a frame adapted to rest on, and to be supported by, the anterior part of the chest or abdomen of a patient on opposite sides of an incision. The frame comprises two, elongated, rigid, blade-supporting elements disposed in opposed relationship to each other with a space between them. A plurality of separate, tissue-engaging blades is supported on each of the rigid elements. The distance between the blades on one of the rigid elements and the blades on the other of the rigid elements is made adjustable, preferably by using a rack and pinion mechanism to effect movement of the rigid elements relative to each other. Each blade is supported on its rigid, blade-supporting element by an associated pylon disposed underneath, and depending from the underside of, the blade-supporting element. Each pylon comprises a laterally extending element connected to the underside of the blade-supporting element, and the blade is connected to the pylon. The pylon is substantially narrower than the width of said blade in the direction of elongation of the blade-supporting element, and consequently the outer layers of fat of an obese patient can accumulate between adjacent pylons, allowing the blades to fully engage the edges of the chest or abdominal wall of the patient at the location of the incision.
In the preferred embodiment of the surgical retractor, each blade supporting element has parallel side edges and the pylons on each blade supporting element are connected to the underside thereof by connections spaced inwardly from the side edges. In this way, clearance is provided to allow an auxiliary instrument support with downwardly projecting side elements embracing the blade-support element, and inwardly projecting flanges engaging the underside thereof adjacent the side edges, to slide along the length of the blade supporting element past the pylons thereon.
As will be apparent, the narrow pylon configuration makes the retractor of the invention especially advantageous for use with obese patients. Moreover, the use of depending pylons with their connections spaced inwardly from the edges of the blade-supporting elements, i.e. the retractor arms, makes it possible for auxiliary instrument supports to be positioned at any desired location on the arms, and to be moved readily along the lengths of the arms.
Other objects, details and advantages of the invention will be apparent from the following detailed description when read in conjunction with the drawings.